Transparent thermocouples based on spray-coated nanocomposites

In this work, we present the use of nanomaterials such as silver nanowires (AgNWs), PEDOT:PSS and single-walled carbon nanotubes (CNTs) as nanocomposites for semi-transparent thermocouples (TCs). All materials are commercially available and are deposited to transparent conducting films by a scalable, facile and low-cost spraying technique. The thin-film TCs are characterized by a purposely developed setup and show Seebeck coefficients as high as 55 µV/°C at a transparency over 86 % at a wavelength of 550 nm for the individual materials, which exceeds the performance of conventional metal based TCs. Moreover, the change in voltage as a function of the temperature difference between the cold and the hot leg shows a linear behavior up to more than 70 °C temperature difference. These findings promote the presented material combinations to good candidates for temperature sensing or even energy harvesting for flexible and wearable electronics.